Valve linkage for steam engine



March 8, 1960 M. w. QUINN 2,927,559

VALVE LINKAGE FOR STEAM ENGINE Filed Jan. 29, 1957 4 Sheets-Sheet 1 Fig./

Marv/n W. Quinn IN V EN TOR.

BY mmv amig March 8, 1960 M. w. QUINN VALVE LINKAGE FOR STEAM ENGINE 4 Sheets-Sheet 2 Filed Jan. 29, 1957 N\ m \\M 8 uv mm mm k ow h mm 8 Q d 9 mm Q 5 arw'n n. Quinn March 8, 1960 w. QUINN 2,927,559

VALVE LINKAGE FOR STEAM ENGINE Filed Jan. 29, 1957 4 Sheets-Sheet 3 Fig.3

Marvin W. Quinn INVENTOR.

March 8, 1960 M. -w. QUINN VALVE LINKAGE FOR STEAM ENGINE 4 Sheets-Sheet 4 Filed Jan. 29, 1957 Marv/n W. 00/00 INVENTOR.

BY file-u details of the linkage;

United States Patent O VALVE LINKAGE non STEAM ENGINE Marvin w. Quinn, St. Paul, Minn. Application January 29, 1957, Serial No. 636,975 Claims. 01. 121-169) The present invention generally relates to a valve actuating linkage and more particularly to a linkage for actuating a radial type valve gear for steam engines with constant valve port openings at all valve cut-off points.

An object of the present invention is to operate separate intake and exhaust valves with linkage having the ability to provide a variable lead to the intake valve.

Another object of the present invention is to provide a valve linkage for steam engines and especially steam locomotives which may be attached to existing installations or assembled onto new installations.

Yet another object of the present invention is to provide a valve linkage in the form of a compact unit mounted within a frame whereby the same could be produced on a production basis for universal use on all steam locomotives with only changes in the linkage from which the unit receives its power in order to adapt the unit to different types and designs of locomotives.

A further important object of the present invention is to provide a valve actuating gear for intake and exhaust valves, in a steam locomotive which receives its motion from the cross head on the main connecting rod and the eccentric crank to which the connecting rod is connected and combine such motion and change it into the proper motion for both the intake and the exhaust valve for the side of the locomotive upon which the unit is mounted.

Yet another feature of the invention is to provide a valve linkage of unit construction with the construction being symmetrical on either side of the longitudinal center line so that the unit may be used on either side 0 the locomotive without change.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals'refer to like parts throughout, and in which:

Figure 1 is a plan view of the valve actuating linkage of the present invention illustrating the frame and certain Figure 2 is a longitudinal, vertical sectional view taken substantially upon the. plane passing along section line 2-2 of Figure 1 illustrating certain details of the linkage mechanism;

Figure 3 is a transverse, vertical sectional view taken substantially upon a plane passing along section line 3-3 of Figure 2;

Figure 4 is a transverse, vertical sectional view taken ice Figure 8 is a perspective view illustrating the linkage arrangement with the support frame omitted;

Figure 9 is a transverse sectional view taken substantially upon a plane passing along section line 9-9 of Figure 2; and v Figure 10 is a transverse vertical sectional view taken substantially upon a plane passing along section line 101tl of Figure 2.

For purposes of illustration, the valve gear shown in the drawings is to scale with the gear beinginstalled on a locomotive with a piston stroke of thirty-two inches. The drawings show the position of the crank pin S and the central position of the arm 38. The angle between the points of maximum travel must be maintained on all installations and this point of maximum travel can be seen on either side of arm 38 which on the right is point B and the corresponding angular position on the left in Figure 2.

Therefore, on an engine of a different stroke, the length of arm 38 would be greater for a longer-stroke engine, and less for a shorter stroke engine. The distance traveled by this arm is unimportant but the angle is of utmost importance since this is necessary to maintain the correct amount of movement of the parts of the valve gear unit.

In positioning this unit on the engine, it should be parallel to the line of motion which would require that the height above the center-line of the main driving axle substantially upon a plane passing along section line 4-4 would in all cases be the same. The reason for this is to keep from changing the dimensions of part 18 as set forth herein. The main driving axle of the locomotive is the center of the circle travelled by the crank pin S. The location of the unit from the center-line of the locomotive in parallel relation to the axle would be governed by the size of the locomotive, clearance of parts and the location of the valve and other mechanical details and the distance ahead of the main driving axle would also have to All of the mechanism within the woulddrive the intake valve through suitable linkage.

As this point is at the front of the unit, at the narrow end, as shown in plan view, Figure 1, it is on the centerline, and therefore, the center of the unit'could approximately correspond to the center-line of the intake valve. The point 48 is the point from which the exhaust valve receives its motion and point 48 is at the bottom of arm 43. This arm is duplicated on the other side generally below point 5 on the plan view or Figure 1 with these arms 4'3 being connected by a cross shaft at point U so they are rigidly interconnected and capable of delivering motion to the exhaust valve from either side. The valve gear unit derives its motion from two points, that is, the cross head 44 and the eccentric crank 41. When the cross head 44, which is connected to the piston and also to the main crank pin 5 as by the main rod, is in its center position the eccentric crank 41 in its forward position. As the engine operates, the two points Sand T are always one-quarter of a turn apart. The main function of the valve gear mechanism is to receive motion from the crosshead 44 and point T, combine it, and change it into the proper motion of both the intake and the exhaust valve for its side of the locomotive.

numeral 1 is a frame which in Figure 2 is cut away approximately on its center-line to clearly show the linkage.

ofi regulating lever 29; point 7 is a bearing for link sup port 25; point 8 is a bearing for part 37; point 9 is a bearing for reversing lever 21; point 10 is a bearing for part 18; point 11 is a bearing for the intake valve bell crank 13 and point 12 is a bearing for the idler arm 17.

As designed, parts 37, 13 and 18 have a fairly long travel. However, the motion from these parts is fairly small, generally around 3 /2 inches. This travel is maintained through the rest of the unit to arms 43 and intake lever 35 where it is increased by the length of these members to inches at the take-oft points respectively 48, and 47.

In order to more clearly explain the operation of the unit, it is broken down into groups of parts which can be explained more easily. Link 24 is the center of operation. This is a link with a sliding block 26 to which is fastened lever 27. As the link 24 must be free to move at both top and bottom, it is supported by link support 25 which is connected to the link 24-at the bottom and carried by the frame 1 by bearings 7.

The link 24 can. be seen in Figure 8 and also in Figure 2 in which itis partially concealed behind the link support 25. The bracket at the bottom of the link 24 to whichthe link support 25 is fastened is wide enough so that clearance is provided for the sliding block 26 and lever 27 to slide all the way to the bottom of link 24. This bracket can be seen in Figures 4 and 8 and is designated by numeral 24a. The slidingblock 26 is slotted at the back side to provide clearance for levers 22 and in Figure 2 and in other figures of the drawings and also in the diagrammatic view shown in Figure 6 which may 23. The link 24 is wider than levers 22 and 23 and is slotted to connect to the same which structure is shown in Figure 4. V

The bottom of link 24'receives motion through lever 22 from the bell crank 18 and. its accompanying linkage.

The bell crank 18 and parts 19 and 22 are clearly shown in the plan view which is Figure 1 and also Figures 2 and 8. Bell crank 18 is also shown in the diagrammatic reverse mechanism in Figure 5 with the bottom part of part 18 omitted. The .bell crank 18 is shown by heavy lines in three positions, that is, center, top and bottom positions of its line of travel. As bell crank 18 receives motion from the eccentric crank 41, it delivers motion to link 24 through levers 22 and 19. The levers 19 are connected at their front end to bell crank 18 and at their rear end toflever 22. At the point or connection of parts 19 1 v and 22, they are'supported by arms 20 of the reversing mechanism. In the diagrammatic view in Figure 5, arms 20 are shown with the reversing mechanism in mid-gear, in forward and in reverse. Part 20 is actually not shown but the arcs O--P in the reverse position, and Q-R in forward are shown as created by part 20 being supported in these respective positions and moved through these arcs by part 19 which receives motion from bell crank 18. When the reverse mechanism is in mid-gear position there is no movement given to lever 22 by the movement of bell crank 18. The pivotal movement of reverse lever 21 controls the operation of the engine.

It is pointed out that other means may be provided for accomplishing the work done by bell crank 18 and its accompanying parts. As an example, an oscillating link and sliding link block. Therefore, the bell crank and its associated parts are not an essential part of-the present invention but since accurate movement is needed at forward-and reverse positions, this is a desirable wayof accomplishing this with a minimum of wear points.

The'top end of link 24 receives motion through lever 23 from the bell crank 13 and its accompanying linkage.

This group of parts is shown atthe re r, end o theframe be termed the intake valve bell crank diagrammatic view. The bell crank 13 is made in halves with a space in between for the parts 14, 15, 16, 17 and 23. Asshown in Figure 6, the bell crank 13 is shown in three positions with heavy lines. The three positions are as follows: Point G shows the bell crank 13 in its central position as'it is shown on Figure 2. It is pointed out that parts 14, 16 and 23 are connected by a common bearing to each other, which, when bell crank 13 is in the central part of its travel, would be in a position slightly below the bearing point 11. In position G part 14 can be seen just below the heavy line .13.

'In the diagrammatic view in Figure 6, just above the intersection of parts 14, 16 and 23 can be seen a vertical line X.. As the cross-head 44 moves from its central position, to the right or rear of the'engine it correspondingly moves parts 38 and 37 which in turn cause the movement of hell crank 13 by the connecting arm 36. When the cross-head 44 causes arm 38 to move to the position A on its arc, the bell crank 13 has moved to the point H as shown in Figure 6. At this time, the bell crank'13 has moved the arm 15 to the position shown. This movement has causedarm 16 to move up and arm 14 hasfbeen moved forward by the upper end of the bell crank-13. This causes the intersection of the parts 14, 16 and-23 to move to the position as indicated by the line labeled Y. The lever 23 at this time has moved the link 24, the sliding block 26, the lever 27 and the top end of part 33 forward an amount equal to the distance indicated by the two vertical lines X to Y. This movement causes part 33 to pivot an equal amount about the bearing point 3. This causes the arm 34 to pull'the intake lever 35 to the rear. ,The point 47 is half again as far from the bearing point 2 as is the connection between arm 34 and lever 35. Therefore, the movement X to Y is increased half again as much which results in the movement indicated by V on the valve drawing which is Figure7. f

In Figure 7, the valve 51 is shown moving in the opposite direction from which it should be moving. When the valve is in this position, it will be seen that the edge of the valve will be in line with the port opening 52 in the casing 53 and any further movementwould admit steam to pass throughthe port opening 52. Therefore, when the cross-head 44 movesfurther to the right, it will cause the arm 38 to move from point A to point B, which will part of'the movement of cross-head 44 causes ,very little movement at theintersection of 14, 16 and23 as shown rom X to Y. However, a small amount of movement,

frompoint A to B causes a larger movement of parts 14, 16 and 23 as shown from Y to Z. In this manner,

I the amount. of valve opening can be the same in all cutoff positions without having an excessive valve travel and in'this particular case the total valve travel is 5% inches through a complete stroke.

When the cross-head 44 moves to the left from its central position, it willcause the bell crank 13 to move down from G on the diagrammatic view. This would again cause part 15 to force part 16 up. However, the fact.

that the bell crank 13 is moving down, the intersection of parts 14, 16 "and 23 will be forced to move to the right, in the opposite direction from positions X, Y and" thus causing the va ve to mo e in t e pp e direction.

As can be readily seen, when the engine ison either dead center regardless of the position of the reverse lever 21, the intake valve will always be at its extreme point of'travel providing the lever 27 is in the position shown in the drawing. It is obvious that in'this positionjthe engine could not operate. However, any movement of the intake valve cut-oil? regulating lever 29 in a downward direction would cause the lever 27 to be partially influenced by the movement of the eccentric crank 41 which would cause the valve to be open longer after the engine has passed its dead-center position than before. By further moving the cut-off lever 29 downward, the point would eventually be reached when the intake valve would not open until after the engine has passed its dead-center position and would remain open through practically the complete stroke of the piston. When the cut-off lever 29 is close to. the upper position, it gives the intake valve lead, as explained above. Dropping the cut-ofi lever 29 to its lower position eliminates the lead, while lengthening the period the intake valve is open which is desirable in this arrangement. It can be seen that with this mechanism, the intake valve has a variable lead, 'or, the shorter the cut-off the further advanced is the point of opening. The fact that when starting and moving slowly, the locomotive can have a valve that will not open until the engine has passed its dead-center position, and remain open for practically the whole stroke,

would be an improvement on commonly employed valve actuating mechanisms. Also, for high speed running, the fact that a locomotive can have a valve opened just ahead of the point of dead-center, open fully and close early in its stroke is an improvement over the presently employed mechanism. Also, this mechanism will allow a selection of any desired valve cut-off to be attained, through the movement of the cut-01f regulating mechanism, from a position just below that shown in the drawing to the bottom of the link 24 and at any point between these limits.

As shown in the drawings, arm 30 is connected to the lower end of cut-01f lever 29. When the cut-off regulating lever 29 is exactly half-way between the upper and lower ends of link 24, arm 30 is moved to cause the lower end of part 31 to move to the point B. This will cause part 31 to pivot about bearing 4 to the position where the upper part of 31 will drop to point E. This in turn will cause arm 32 to move the link block 34a which is connected to arm 34 down to the position F on part 33. As 33 is pivoted at bearing 3 and the distance from F to the bearing 3 is twice as far as from its original position, any movement of lever 27 will be doubled at point F. This is a necessary function inasmuch as link 24 is at its point of extreme travel at one end and the other end of the same part is in its central position. Therefore, the center of the link 24 will only be moved half as far as the end which has reached the point of extreme travel. Consequently, when the link block 26 is in this position, the movement of parts 30, 31 and 32 to the point Where arm 34 is at point F is necessary to maintain the correct valve travel.

When the cut-off regulating lever 29 is moved downward further, the end of lever 29 which is connected to arm 30 would eventually reach the point C which can be seen near number 6. At this position, the parts 31 and 32 are moved until they are once more in the positions in the drawings.

The exhaust valve which is separate from the intake valve receives its motion from point 48 and has the same travel and time of valve opening at all times as it is not controlled by the cut-off lever 29. This is desirable as it will practically eliminate back pressure caused by restriction at the exhaust port. This back pressure is a fault common to the widely used valve gears.

Arm 43 is pivoted on the end of exhaust advance lever 45 which is pivoted at bearing 5. Arm 42, which takes motion from the bottom end of link 24 and sup plies motion to the point U on arm 43 accounts for the exhaust valve travel except for a small amount received from part 37 through arm 46 and lever 45 with its hearing at 5. The small movement received from part 37 is used for advance of the exhaust valve. When the cross-head 44 is at the end of its travel, point Tv When arm 38 has moved on 37 to point B, arm 37 has given a movement to the upper end of arm 43 thus causing arm 43 to pivot about the point U which movespoint 48 on arm 43 an amount equal to V on the valve drawing in Figure 7. At this time, any further movement of the engine will cause the exhaust valve to open. In this way as soon as the engine passes the dead-center point, the steam which has been used and expanded will begin to exhaust and continue to do so for practically the entire exhaust stroke.

The linkage mechanism of the present invention is intended to be an improvement over existing types of valve gear which are used to control the timing of events with slide valves for reciprocating steam engines. The most commonly used types of valve gear on locomotives are this type, using one valve for each cylinder, to control both intake and exhaust of steam. As the valve cut-01f point is shortened with this common type of gear for high speed running or any speed other than starting and very slow movement, the valve travel is also shortened which restricts the admission of steam to the cylinder and the exhaust from the cylinder is likewise restricted.

By way of comparison, the present invention can operate an intake valve and an exhaust valve of ten inches in diameter with respective port openings of 43.8 square inches for the intake and 46.8 square inches for the ex haust. As the ports are fully opened at all cut-0E positions, a cut-off for instance, twenty-five percent of the piston travel, will give a port opening as much as three times as large as will the existing types of valve gear. It should be pointed out that the exhaust valve will not be controlled by the cut-01f regulating lever therefore it gives a free exhaust practically the complete exhaust stroke. From the standpoint of accessibility and ease of repair, it would not be diflicult to remove this unit from a locomotive for repair in case of break-down as all of the parts are mounted within a frame which can be easily bolted to the locomotive. This could be done without removing any of the running gear or valves from the locomotive as all of the connections to these parts are through exposed linkage. The previously mentioned sizes and dimensions are not intended to restrict the inventive con-' cept in this application to this particular size since the actuating mechanism may be adapted for use with various types of loco-motives having difierent length of stroke and other size variations. It is thought that by reviewing Figures 2 and 8 specifically as well as the diagrammatic views, the movement of the various elements and parts constituting the actuating linkage may be easily followed.

Theforegoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. An actuating mechanism for the intake valve of a steam engine comprising a linkage system receiving motion from the reciprocating piston crosshead and an cecentric pin on thedrive axle, said linkage system including an actuating arm for connection with the intake valve,

saidclinkage. ystem,,inc i d ng means f r m ining me -1 tion received from, the two sources and moving the actuat ingar-m andintake valve from atully closed to a fully open-position during a very small movement of the piston head for varying the lead of the intake: valve opening a's the speed of movement of the crosshead varies.

2. The combination of claim 1 wherein said regulating mechanism inclndes'a rockable lever forming a part of the linkage system, a block slidably mounted on said lever, said block being interconnected with said actuating arm through a fixed length lever system whereby longitudinalmovernent of the block on the rockable lever will vary thepoint of opening movement of the operating link for varying the point of opening of the intake valve.

3. An operating mechanism for an intake valve andan exhaust valve of a steam engine, said mechanism comprising a 7 generally open rectangular frame, an exhaust valve operating arm adapted to be connected with an exhaust valve with the lever beingpivotally carried on said frame, an intake valve operating levenadapted to be connected to an intake valve and being carried by said frame for swinging movement in a vertical plane, a

first input bellcrank carried bythe'frame and adapted to receive oscillatory motion from an eccentric crank on the drive axle, a second input bellcrank carried by the frame and adapted to receive oscillatory movement from a reciprocating crosshead, and a linkage mechanism carried by the frame and receiving motion from the first and} second input bellcranks and imparting motion to the op erating lever and operating arm, said linkage mechanism including a generally vertically disposed link, link supporting means pivotally attached to the link adjacent the bottom thereof and pivotally connected to the frame at ing the scope of movement of the exhaust valve operating arm for varying the point of opening of an exhaust valve, said linkage means interconnecting the link and the intake valve operating lever including intake valve cut oil lever, means having sliding connection with said link for varying the scopeof movement of the intake valve operating lever for varying the point of opening of an intake valve. i

4. The structure as defined in claim 3 wherein said lever system interconnecting the lower end of the link and the first input bellcrank includes a reverse lever means for altering the movement imparted to the link by said first input bellcrank.

'5. The structure as defined in claim 4 wherein said lever system interconnecting the link and the intake valve operatinglever includes a sliding link block mounted on a swingablearm and connected with the intake valve operating lever for varying the scope of movement thereof.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Iversen Feb. 19, 1907" Bacon Sept. 15, 1931 

